The invention relates to a high voltage metal-clad circuit breaker having an elongated vertical metal tank, obturated by a top cover and filled with a high dielectric strength gas, the active part of the circuit breaker having a column-shape which is placed in the tank and lies on the lower bottom of the tank by insulating feet.
A metal-clad circuit breaker of the type mentioned, for example described in U.S. Pat. No. 3,895,202, can reach a height of severals meters, and the oscillations resulting from a shock during shipment or when an earthquake occurs, can generate excessive stresses and damage of the active part located in the tank. The conventional solutions of clamping the active part during shipment cannot be applied when the tanks are sealed and filled with gas at the factory, and they do not solve the problems about earthquakes.
An object of the present invention is to remedy these disadvantages and to permit the realization of a strong fixing device allowing for differential thermal expansion of the constituent parts of the circuit breaker.
In accordance with the invention, the circuit breaker is characterized by the fact that the upper part of the column is secured to the tank by at least two elastic stays capable of exerting a radial component to maintain the column in position.
The stays radially extend between the upper part of the column and the cover, the stays being regularly distributed on the column circumference. The elasticity of the stays permits a compensation of thermal expansions enough to limit the stresses exerted on the active part of the circuit breaker. The number of stays can be increased depending of the intensities of forecast earthquakes, the minimal number being two. The stays are constituted by an insulating rod ensuring the insulation between the active part of the circuit breaker and the generally grounded metal tank, the insulating rod carrying at its ends anchor parts, one of which presents a set screw. The stay shows an elasticity compression and traction from a rest equilibrium position, and the adjusting device does not exert a force on the active part of the circuit breaker. The mounting of the action part of the circuit breaker is carried out at a temperature of 15.degree. to 20.degree. C. When the temperature increases or decreases, the stays will be compressed or stretched but will always ensure a force to center the column. It is advantageous to hinge the stays on the upper part of the column for preventing any sticking of the column.